574 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
them occupying the median sulcus. It is quite unlike C. minuta, another small 
species, in the uncertain character of the costae. No other species are comparable. 
CAMERELLA OBESA Cooper, new species 
Plate 116, D, figures 25-34 
Shell of about medium size for the genus, slightly wider than long and with 
the greatest width anterior to the middle; outline subpentagonal; apical angle 
about 100°. Sides narrowly rounded; anterolateral margins short, sloping 
strongly toward the middle; valves unequally convex, the brachial valve having 
the greater convexity. Surface mostly smooth, but anterior extension of tongue 
marked by 2 costae, anterior end of fold marked by 3 short costae, and anterior 
surface of flanks by 2 costae. 
Pedicle valve gently convex in lateral profile and broadly but slightly convex 
in anterior profile ; umbonal and median regions gently inflated ; sulcus short and 
shallow, defined by 2 short anterior folds; tongue bent at a right angle, long, 
serrate, and with a truncated front; beak short. 
Brachial valve fairly strongly convex in lateral profile but strongly domed in 
anterior profile ; median region and umbo swollen; fold short and inconspicuous ; 
flanks swollen and with precipitous sides. 
Measurements in mm.—Holotype, length 9.6, brachial length 9.1, width 10.7, 
hinge width 2.1, thickness 8.3. 
Types.—Holotype: 117140a; unfigured paratype: 117140b. 
Horizon and locality—Rockland formation in New York: On Mill Creek, 
Turin, Port Leyden (15’) Quadrangle. 
Discussion.—This species is like a small C. volborthi in its noncostate posterior 
and its obese form, but it is a much smaller species having a wider and squarer 
tongue on the pedicle valve. It is larger and ornamented by stronger costae than 
C. tumida from Newfoundland. Camerella obesa is similar to C. ventricosa from 
the Crown Point formation but differs in having a more strongly geniculated 
tongue and less strong costae. 
CAMERELLA OKLAHOMENSIS Cooper, new species 
Plate 71, F, figures 27-35 
Shell of about medium size for the genus, slightly wider than long; brachial 
valve deeper than the pedicle valve; apical angle approximately a right angle; 
widest at the middle; surface semicostate, 3 costae on the fold, 2 in the sulcus, 
and 4 to 5 on the flanks. 
Pedicle valve moderately convex in lateral profile with a bulge just posterior 
to the middle ; anterior profile gently convex ; sulcus originating abruptly a short 
distance anterior to the middle; sulcus narrow, moderately deep; tongue short; 
median region swollen; flanks narrowly rounded and with steep slopes. 
Brachial valve strongly convex in lateral profile, strongly domed in anterior 
profile. Median region and flanks swollen and tumid. Fold low, short, originat- 
ing anterior to the middle. Lateral slopes precipitous. 
